1. Field of the Invention
This invention relates to an engine for a vehicle with a cam chain tensioner actuated by the pressure of lubricating oil for stabilizing the movement of a cam chain.
2. Description of Related Art
In an engine for a vehicle for transmitting rotation of a crankshaft to cam shafts, a system has been known in which a cam chain tensioner using a plunger adapted to be pushed out by oil pressure, is provided to stabilize the movement of a cam chain.
In some cam tenioners of this type, a passage through which lubricating oil is supplied to the cam tensioner, is provided with a delivery pipe separate from a crankcase and lubricating oil is supplied to the cam chain tensioner through the delivery pipe. In a system with piping such as a separate delivery pipe as described above, it is necessary that interference with other members is avoided, which places restrictions on the layout and increases the number of parts, causing increased manufacturing costs.
In some systems, the cam chain tensioner is mounted to a head cylinder and lubricating oil is supplied to the cam chain tensioner from a lubricating oil passage formed in the head cylinder. In this case, however, the pressure of the lubricating oil is decreased because of the lubricating oil being supplied from the lubricating oil passage in the head cylinder on the downstream side, or the pressure of lubricating oil is decreased because of air mixed in the lubricating oil.